The p38 MAPK pathway is critical for 5,5'-dibromodiindolylmethane-induced apoptosis to prevent oral squamous carcinoma cells

3,3'-Diindolylmethane and indole-3-carbinol: potential therapeutic molecules for cancer chemoprevention and treatment via regulating cellular signaling pathways

Dietary compounds in cancer prevention have gained significant consideration as a viable method. Indole-3-carbinol (I3C) and 3,3'-diindolylmethane (DIM) are heterocyclic and bioactive chemicals found in cruciferous vegetables like broccoli, cauliflower, cabbage, and brussels sprouts. They are synthesized after glycolysis from the glucosinolate structure. Clinical and preclinical trials have evaluated the pharmacokinetic/pharmacodynamic, effectiveness, antioxidant, cancer-preventing (cervical dysplasia, prostate cancer, breast cancer), and anti-tumor activities of I3C and DIM involved with polyphenolic derivatives created in the digestion showing promising results. However, the exact mechanism by which they exert anti-cancer and apoptosis-inducing properties has yet to be entirely understood. Via this study, we update the existing knowledge of the state of anti-cancer investigation concerning I3C and DIM chemicals. We have also summarized; (i) the recent advancements in the use of I3C/DIM as therapeutic molecules since they represent potentially appealing anti-cancer agents, (ii) the available literature on the I3C and DIM characterization, and the challenges related to pharmacologic properties such as low solubility, and poor bioavailability, (iii) the synthesis and semi-synthetic derivatives, (iv) the mechanism of anti-tumor action in vitro/in vivo, (v) the action in cellular signaling pathways related to the regulation of apoptosis and anoikis as well as the cell cycle progression and cell proliferation such as peroxisome proliferator-activated receptor and PPARγ agonists; SR13668, Akt inhibitor, cyclins regulation, ER-dependent-independent pathways, and their current medical applications, to recognize research opportunities to potentially use these compounds instead chemotherapeutic synthetic drugs.

Studies on the mode of action of synthetic diindolylmethane derivatives against triple negative breast cancer cells

Diindolylmethane (DIM) is a metabolic product of indole-3-carbinol (I3C), the major phytochemicals present in cruciferous vegetables, which can modulate multiple signalling pathways in cancer. The present study deals with the mechanism of action of two synthetic biaryl conjugates of DIM in triple negative breast cancer cells. Out of twelve DIM derivatives tested, two compounds, DIM-1 and DIM-4, exhibit cytotoxicity with GI₅₀ values of 9.83±0.2195 μM and 8.726±0.5234 μM, respectively, in 2D culture. In 3D culture, DIM-1 and DIM-4 show GI₅₀ values of 24.000±0.7240 μM and 19.230±0.3754 μM, respectively. The non-toxic nature of the compounds was also established by the toxicity studies using the zebrafish model system. The two compounds induced apoptosis and anoikis in the cancer cells, which was confirmed by morphological analysis, nuclear fragmentation, membrane integrity assay, caspase activity measurements, and modulation of pro/anti-apoptotic proteins. The compounds inhibited cell migration and MMP-2 and MMP-9 activities indicating their anti-metastatic property. They also reduced the expression of active Ras, phosphorylated forms of PI3K, Akt and mTOR. Immunofluorescence studies revealed the reduced expression of EGFR and pEGFR in treated cells. To conclude, DIM-1 and DIM-4 induced anti-breast cancer effects by blocking EGF receptor and subsequently inhibiting Ras-mediated PI3K-Akt-mTOR signalling pathway.

Contribution of p38 MAPK Pathway to Norcantharidin-Induced Programmed Cell Death in Human Oral Squamous Cell Carcinoma

Norcantharidin (NCTD), a demethylated analog of cantharidin isolated from blister beetles, has been used as a promising anticancer agent; however, the underlying function of NCTD against human oral squamous cell carcinoma (OSCC) has not been fully understood. Here, this study was aimed to investigate the apoptotic effect and molecular targets of NCTD in human OSCC in vitro and in vivo. The anticancer effects of NCTD and its related molecular mechanisms were evaluated by trypan blue exclusion assay, live/dead assay, western blotting, 4-6-Diamidino-2-Phenylindole (DAPI) staining, flow cytometric analysis, Terminal Deoxynucleotidyl Transferase dUTP Nick end Labeling (TUNEL) assay, and immunohistochemistry. NCTD significantly inhibited cell growth and increased the number of dead cells in HSC-3 and HN22 cell lines. It induced the following apoptotic phenomena: (1) the cleavages of poly (ADP-ribose) polymerase and casepase-3; (2) increase in apoptotic morphological changes (nuclear condensation and fragmentation); (3) increase in annexin V-positive cells or sub-G₁ population of cells. NCTD significantly activated the p38 mitogen-activated protein kinase (MAPK) pathway but inactivated the signal transducer and activator of transcription (STAT)3 pathway. A p38 MAPK inhibitor (SB203580) partially attenuated NCTD-induced programmed cell death (apoptosis) in both cell lines, whereas ectopic overexpression of STAT3 did not affect it. NCTD strongly suppressed tumor growth in the tumor xenograft bearing HSC-3 cells, and the number of TUNEL-positive cells increased in NCTD-treated tumor tissues. In addition, NCTD did not cause any histopathological changes in the liver nor the kidney. NCTD induced programmed cell death via the activation of p38 MAPK in OSCC. Therefore, these results suggest that NCTD could be a potential anticancer drug candidate for the treatment of OSCC.

Targeting the unfolded protein response in head and neck and oral cavity cancers

Many FDA-approved anti-cancer therapies, targeted toward a wide array of molecular targets and signaling networks, have been demonstrated to activate the unfolded protein response (UPR). Despite a critical role for UPR signaling in the apoptotic execution of cancer cells by many of these compounds, the authors are currently unaware of any instance whereby a cancer drug was developed with the UPR as the intended target. With the essential role of the UPR as a driving force in the genesis and maintenance of the malignant phenotype, a great number of pre-clinical studies have surged into the medical literature describing the ability of dozens of compounds to induce UPR signaling in a myriad of cancer models. The focus of the current work is to review the literature and explore the role of the UPR as a mediator of chemotherapy-induced cell death in squamous cell carcinomas of the head and neck (HNSCC) and oral cavity (OCSCC), with an emphasis on preclinical studies.

Solvent-Free Addition of Indole to Aldehydes: Unexpected Synthesis of Novel 1-[1-(1H-Indol-3-yl) Alkyl]-1H-Indoles and Preliminary Evaluation of Their Cytotoxicity in Hepatocarcinoma Cells

New 1-[1-(1H-indol-3-yl) alkyl]-1H-indoles, surprisingly, have been obtained from the addition of indole to a variety of aldehydes under neat conditions. CaO, present in excess, was fundamental for carrying out the reaction with paraformaldehyde. Under the same reaction conditions, aromatic and heteroaromatic aldehydes afforded only classical bis (indolyl) aryl indoles. In this paper, the role of CaO, together with the regiochemistry and the mechanism of the reaction, are discussed in detail. The effect of some selected 3,3′- and 1,3′-diindolyl methane derivatives on cell proliferation of the hepatoma cell line FaO was also evaluated.

Anticancer activity of synthetic bis(indolyl)methane-ortho-biaryls against human cervical cancer (HeLa) cells

Bis(indolyl)methane appended biaryls were designed, synthesized and evaluated in human cervical cancer cell lines (HeLa) for their anticancer activities and compared against normal rat cardiac myoblasts (H9C2) cells. Compounds 1-12 were synthesized, with variations in one of the phenyl unit, in a single step by condensation of biaryl-2-carbaldehydes with indole in the presence of para-toluenesulfonic acid. Compound 1 exhibited a GI50 value of 11.00 ± 0.707 μM and the derivatives, compounds 4 and 11 showed a GI50 value of 8.33 ± 0.416 μM and 9.13 ± 0.177 μM respectively in HeLa cells and was found to be non-toxic to H9C2 cells up to 20 μM. Furthermore, compounds 1, 4 and 11 induced caspase dependent cellular apoptosis in a concentration-dependent manner, reduced mitochondrial membrane potential, inhibited the cell migration and downregulated the production of MMP-2 and MMP-9 in HeLa cells.

Multiple therapeutic and preventive effects of 3,3'-diindolylmethane on cancers including prostate cancer and high grade prostatic intraepithelial neoplasia

Cruciferous vegetables belong to the plant family that has flowers with four equal-sized petals in the pattern of a crucifer cross. These vegetables are an abundant source of dietary phytochemicals, including glucosinolates and their hydrolysis products such as indole-3-carbinol (I3C) and 3,3′-diindolylmethane (DIM). By 2013, the total number of natural glucosinolates that have been documented is estimated to be 132. Recently, cruciferous vegetable intake has garnered great interest for its multiple health benefits such as anticancer, antiviral infections, human sex hormone regulation, and its therapeutic and preventive effects on prostate cancer and high grade prostatic intraepithelial neoplasia (HGPIN). DIM is a hydrolysis product of glucosinolates and has been used in various trials. This review is to provide an insight into the latest developments of DIM in treating or preventing both prostate cancer and HGPIN.

Attenuation of multi-targeted proliferation-linked signaling by 3,3'-diindolylmethane (DIM): from bench to clinic

Emerging evidence provide credible support in favor of the potential role of bioactive products derived from ingesting cruciferous vegetables such as broccoli, brussel sprouts, cauliflower and cabbage. Among many compounds, 3,3'-diindolylmethane (DIM) is generated in the acidic environment of the stomach following dimerization of indole-3-carbinol (I3C) monomers present in these classes of vegetables. Both I3C and DIM have been investigated for their use in preventing, inhibiting, and reversing the progression of cancer - as a chemopreventive agent. In this review, we summarize an updated, wide-ranging pleiotropic anti-tumor and biological effects elicited by DIM against tumor cells. It is unfeasible to point one single target as basis of cellular target of action of DIM. We emphasize key cellular and molecular events that are effectively modulated in the direction of inducing apoptosis and suppressing cell proliferation. Collectively, DIM orchestrates signaling through Ah receptor, NF-κB/Wnt/Akt/mTOR pathways impinging on cell cycle arrest, modulation of key cytochrome P450 enzymes, altering angiogenesis, invasion, metastasis and epigenetic behavior of cancer cells. The ability of DIM to selectively induce tumor cells to undergo apoptosis has been observed in preclinical models, and thus it has been speculated in improving the therapeutic efficacy of other anticancer agents that have diverse molecular targets. Consequently, DIM has moved through preclinical development into Phase I clinical trials, thereby suggesting that DIM could be a promising and novel agent either alone or as an adjunct to conventional therapeutics such as chemo-radio and targeted therapies. An important development has been the availability of DIM formulation with superior bioavailability for humans. Therefore, DIM appears to be a promising chemopreventive agent or chemo-radio-sensitizer for the prevention of tumor recurrence and/or for the treatment of human malignancies.